Description
Hexanal has a fatty, green, grassy, powerful, penetrating characteristic fruity odor and taste (on dilution).
It is prepared from the calcium salt of caproic acid and formic
acid.
Chemical Properties
Hexanal occurs in apple and strawberry aromas as well as in orange and lemon oil. It is a colorless
liquid with a fatty, green odor and, in low concentration, is reminiscent of unripe
fruit. Hexanal is used in fruit flavors and, when highly diluted, in perfumery for
obtaining fruity notes.
Chemical Properties
Colorless liquid; sharp aldehyde odor.Immiscible with water.
Occurrence
Reported found that hexanal occurs naturally in in some natural aromas of apple, strawberry, camphor oil, tea extracts, tobacco leaves,
Eucalyptus globulus, dwarf pine, bitter orange and coffee. Also reported found in nearly 300 natural sources including apple, apricot,
banana, sweet and sour cherry, citrus peel oils and juices, berries, guava, melon, raisins, peach, pear, papaya, pineapple, asparagus,
cabbage, celery, carrot, lettuce, shallots, onion, leek, ginger, parsley, bread, cheeses, butter, milk, fish, meats, cocoa, coffee, tea, nuts,
popcorn, potato chips, oat products, honey, soybean, plum, cauliflower, beetroot, celery root, figs, cardamom, coriander seed and leaf,
brussel sprouts, rice, quince, radish, lovage, corn oil, laurel and malt
Uses
Hexanal is used in the flavor industry to prepare fruity flavors. It is utilized as a flavoring agent in the food industry. It is also used in Witting and aldol reactions.
Uses
Hexanal occurs naturally inmany foods, such as in ripening
fruits, or because of addition as a flavorant; it has an apple taste. It can also be produced in foods because of lipid
peroxidation during cooking. It is mainly used as a food
flavorant, in fragrances, and in the manufacture of dyes,
plasticizers, synthetic resins, and pesticides. It is released to
air and water during production or use for the manufacture
of other products or during the use of these products
themselves. It undergoes oxidation and polymerization
readily.
Feron et al. identified hexanal in about 80 different
types of food.
Definition
ChEBI: A fatty aldehyde that is hexane in which one of the terminal methyl group has been mono-oxygenated to form the corresponding aldehyde.
Preparation
Prepared from the calcium salt of caproic acid and formic acid
Aroma threshold values
Detection: 4.1 to 22.8 ppb; recognition: 400 ppb; aroma characteristics at 2.0%: green, fatty, leafy, vegetative, fruity and clean with a woody nuance
Taste threshold values
Taste characteristics at 2.5 ppm: green, woody, vegetative, apple, grassy, citrus and orange with a fresh,
lingering aftertaste
Synthesis Reference(s)
Journal of the American Chemical Society, 93, p. 1693, 1971
DOI: 10.1021/ja00736a021
General Description
A clear colorless liquid with a pungent odor. Flash point 90°F. Less dense than water and insoluble in water. Vapors heavier than air.
Air & Water Reactions
Highly flammable. Insoluble in water.
Reactivity Profile
Caproaldehyde is an aldehyde. Aldehydes are frequently involved in self-condensation or polymerization reactions. These reactions are exothermic; they are often catalyzed by acid. Aldehydes are readily oxidized to give carboxylic acids. Flammable and/or toxic gases are generated by the combination of aldehydes with azo, diazo compounds, dithiocarbamates, nitrides, and strong reducing agents. Aldehydes can react with air to give first peroxo acids, and ultimately carboxylic acids. These autoxidation reactions are activated by light, catalyzed by salts of transition metals, and are autocatalytic (catalyzed by the products of the reaction). The addition of stabilizers (antioxidants) to shipments of aldehydes retards autoxidation. May attack some forms of plastics [USCG, 1999].
Hazard
Flammable, moderate fire risk.
Health Hazard
Ingestion causes irritation of mouth and stomach. Contact with vapor or liquid irritates eyes. Liquid irritates skin.
Fire Hazard
Behavior in Fire: Vapor is heavier than air and may travel to a source of ignition and flash back.
Chemical Reactivity
Reactivity with Water No reaction; Reactivity with Common Materials: May attack some plastics; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.
Toxics Screening Level
The initial threshold screening level (ITSL) for hexanaldehyde is 2 μg/m3 based on an annual averaging time.
